A Comparative Analysis of the Anti-Tumor Activity of Sixteen Polysaccharide Fractions from Three Large Brown Seaweed, Sargassum horneri, Scytosiphon lomentaria, and Undaria pinnatifida.

Searching for natural products with anti-tumor activity is an important aspect of cancer research. Seaweed polysaccharides from brown seaweed have shown promising anti-tumor activity; however, their structure, composition, and biological activity vary considerably, depending on many factors. In this study, 16 polysaccharide fractions were extracted and purified from three large brown seaweed species (Sargassum horneri, Scytosiphon lomentaria, and Undaria pinnatifida). The chemical composition analysis revealed that the polysaccharide fractions have varying molecular weights ranging from 8.889 to 729.67 kDa, and sulfate contents ranging from 0.50% to 10.77%. Additionally, they exhibit different monosaccharide compositions and secondary structures. Subsequently, their anti-tumor activity was compared against five tumor cell lines (A549, B16, HeLa, HepG2, and SH-SY5Y). The results showed that different fractions exhibited distinct anti-tumor properties against tumor cells. Flow cytometry and cytoplasmic fluorescence staining (Hoechst/AO staining) further confirmed that these effective fractions significantly induce tumor cell apoptosis without cytotoxicity. qRT-RCR results demonstrated that the polysaccharide fractions up-regulated the expression of Caspase-3, Caspase-8, Caspase-9, and Bax while down-regulating the expression of Bcl-2 and CDK-2. This study comprehensively compared the anti-tumor activity of polysaccharide fractions from large brown seaweed, providing valuable insights into the potent combinations of brown seaweed polysaccharides as anti-tumor agents.

Long-Term Krill Oil Administration Alleviated Early Mild Cognitive Impairment in APP/PS1 Mice.

SCOPE: Alzheimer's disease is an age-dependent neurodegenerative disorder. Mounting studies focus on the improvement of advanced cognitive impairment by dietary nutrients. Krill oil (KO), a rich source of DHA/EPA and astaxanthin, is effective in improving cognitive function. The study mainly investigates the protective effects of long-term KO administration on early cognitive impairment. METHODS AND RESULTS: Results show that 2 months KO administration (50 and 100 mg kg-1 BW) can dramatically promote learning and memory abilities. Mechanism studies demonstrate that KO reduces amyloid ß concentration by regulating the amyloidogenic pathway, inhibits neuro-inflammation via regulating TLR4-NLRP3 signaling pathway, and prevents neuron injure. KO supplementation also enhances gut barrier integrity, reduces serum lipopolysaccharide leakage, and alters the gut microbiota by reducing Helicobacteraceae, Lactobacillaceae proportion, increasing Dubosiella and Akkermansia relative abundance. Particularly, a significant increase of isovaleric acid, propionic acid, and acetic acid levels is observed after KO supplementation. Correlation analysis shows that short-chain fatty acids (SCFAs), gut microbiota, and cognitive function are strongly correlated. CONCLUSIONS: The results reveal that KO relieves early mild cognitive impairment possibly for its role in mediating the gut microbiome-SCFAs-brain axis. Thus, KO may provide potential intervention strategies to prevent cognitive impairment in the early stages through the microbiota-gut-brain axis.

α-D-1,6-glucan from Castanea mollissima Blume alleviates dextran sulfate sodium-induced colitis in vivo.

A homogenous α-D-1,6-glucan (CPA) was extracted from Castanea mollissima Blume. The effect of CPA on ameliorating dextran sulfate sodium induced colitis was investigated. CPA repressed TNF-α and IL-1ß level in LPS stimulated RAW264.7 cells. After the intragastric administration of CPA (200 or 400 mg/kg/day), the colon length and body weights of mice with colitis increased and the disease activity index reduced. CPA alleviated colon tissue damage by elevating ZO-1 and occludin protein levels and regulating TNF-α and IL-1ß by inhibiting the protein expression of NLPR3 and NF-κB p65. The abundance of Bacteroidetes and Firmicutes was altered and short-chain fatty acid (SCFA) levels, especially propionic, butyric, and isovaleric acids increased significantly. These results indicated that CPA could alleviate colitis by protecting mucosal barriers, reducing inflammation, and regulating intestinal microbiota and SCFA levels. Thus, CPA can be developed as a functional food for the prevention and treatment of colitis.

Effect of the structural characterization of the fungal polysaccharides on their immunomodulatory activity.

The immunomodulatory effects of the four extracellular polysaccharides, namely WPA, WPB, AP2A, and TP1A, which were isolated from the fermented broth of Aspergillus aculeatus, A. terreus and Trichoderma sp. KK19L1, were investigated in vitro. WPA, WPB, AP2A, and TP1A were not toxic to RAW264.7 cells. These polysaccharides enhanced cell viability. WPA, WPB, AP2A, and TP1A showed increased immunomodulatory effect by strengthening the phagocytic activity and enhancing the release of NO, TNF-α and IL-6 from RAW264.7 cells. WPA, WPB, AP2A, and TP1A exhibited different immunomodulatory activity in vitro due to their different structural characterizations, and their immunoregulatory effects decreased successively in the following order: WPA, WPB, AP2A, and TP1A. The extracellular polysaccharides WPA, WPB, AP2A, and TP1A had potent immunomodulatory effects and could be used as potential immunomodulatory agents in the fields of functional food and medicine.

Biocompatibility of Alexandrium minutum in the growth and paralytic shellfish toxins production under five cultivation methods.

This study evaluated the performance of an easy-cultivation device for the mass culture of Alexandrium minutum (A. minutum), a dinoflagellate that produces paralytic shellfish toxins (PSTs). Five culture conditions including three different sizes of containers (250 mL conical flask, 500 mL beaker, and 20 L jar) in two different environments (out-incubator and incubator) were compared in terms of growth and PSTs production. Compared with the incubator environment, the out-incubator environment had more fluctuations in temperature and light intensity. Results showed that the cell densities of A. minutum increased in all groups, especially in the conical flask (I, out-incubator, 6.29×106 cells/mL) and the beaker (IV, incubator, 7.28×106 cells/mL). When cultured in the 20 L jar under out-incubator condition, the algae had the lowest cell density (2.82×106 cells/mL) but the highest toxicity (93.42 ± 2.55×10-6 MU/cell). The negative correlation between average growth rate and single-cell toxicity could be explained by biocompatibility, thereby indicating that the low growth rate led to high toxicity. HPLC-FLD showed that the cellular toxicity increased due to the quantitative increase in GTX1/4, which are the more toxic derivatives. The PSTs types consistently contained GTX1/4 and GTX2/3. The differences in algae growth and toxin-production could be due to changes in bacteria (out-incubator) and CO2 (incubator) with vessel size. The effects of environmental factors on algae are strain specific. The out-incubator device can be applied for large-scale cultivation of A. minutum considering the algae density and toxin-producing ability.

Structural characterization of arabinogalactan extracted from Ixeris chinensis (Thunb.) Nakai and its immunomodulatory effect on RAW264.7 macrophages.

An arabinogalactan (ICPA) was isolated from the water extract of Ixeris chinensis (Thunb.) Nakai. ICPA was mainly composed of galactose and arabinose with minor amount of glucose. The molecular weight of ICPA was 58.1 kDa. Structural analysis by methylation and NMR spectroscopy indicated that ICPA contained α-D-Glcp(1→, →5)-α-L-Araf(1→, ß-D-Galf(1→, →3)-ß-D-Galf(1→, ß-D-Galp(1→, →6)-ß-D-Galp(1→, and â†’ 3,6)-ß-D-Galp(1→, and that the molar ratio of the sugar residues was about 0.1:1.0:0.1:0.2:1.1:1.0:1.3, respectively. The immunomodulatory activity on RAW264.7 cells was measured in vitro. ICPA stimulated RAW 264.7 cell proliferation at 25-400 µg/mL in a dose-dependent manner. ICPA also enhanced phagocytosis, and the secretion of NO, TNF-α, and IL-6 by the cells. The results suggested the potential utilization of ICPA as an immunomodulatory agent.

A label-free aptasensor for turn-on fluorescent detection of ochratoxin A based on aggregation-induced emission probe.

A novel label-free fluorescence aptasensor used for the detection of ochratoxin A (OTA) is presented in this study. When aggregated on the surface of DNA aptamer, aggregation-induced emission (AIE) fluorescence probe presents turn-on fluorescence property. The method proposed in this article was based on an AIE probe, 4, 4-(1E,1E)-2, 2-(anthracene-9, 10-diyl) bis (ethene-2, 1-diyl) bis (N, N, N-trimethylbenzenaminium iodide) (DSAI). With OTA present, the aptamer will combine with OTA and the conformation of the aptamer will switch to an antiparallel G-quadruplex from the initial random coil, which obstructs its digestion by Exo I. After the solution is added with DSAI, DSAI will aggregate on the surface of the aptamer/OTA complex and produces a strong emission. In the range of 5 to 500 ng · ml-1 OTA concentrations, the fluorescence increases with a linear logarithm relationship. The detection limit is 1.9 ng · ml-1. This method was used to detect OTA in spiked real samples, with recoveries and RSDs in the range of 92.2% to 106.3%, and 2.7% to 5.2%, respectively.

A label-free fluorometric aptasensor for adenosine triphosphate (ATP) detection based on aggregation-induced emission probe.

Based on Aggregation-Induced Emission (AIE), the development of a label-free, simple and sensitive fluorometric aptasensor for adenosine triphosphate (ATP) detection is described. With ATP present, the aptamers will combine with ATP and the conformation of the aptamer will switch from a random coil to an antiparallel G-quadruplex, which impedes the digestion by exonuclease I (Exo I). Addition of 4,4 -(1E,1E)-2,2-(anthracene-9,10-diyl) bis (ethene-2,1-diyl) bis (N,N, N-trimethyl-benzenaminium iodide) (DSAI) into the solution will cause aggregation of DSAI on the surface of the aptamer/ATP complex and consequently give rise to strong emission. Additionally, a good linear relationship was observed under optimized conditions between the fluorescence intensities and the logarithm of ATP concentrations (R2 = 0.9908). The established aptamer sensor was highly sensitive and exhibited a low limit of detection of 32.8 nM, with superior specificity for ATP. It was also used in the quantification of ATP levels in human serum samples and demonstrated satisfactory recoveries in the scope of 93.2%-107.6%. The cellular ATP assay results indicated that the developed method can be used for monitoring ATP concentrations in cell extracts without the interference of other substances in the cells. This method offers several advantages such as simplicity, rapidity, low cost and excellent selectivity, which make it hold great potential for the detection of ATP in bioanalytical and biological studies.

[Study on the pyrolysis behavior of geranyl-beta-D-glucopyranoside by gas chromatography-mass spectrometry].

In order to investigate the pyrolysis behavior of the flavor precursor of geranyl-beta-D-glucopyranoside, the glycoside was pyrolyzed at 200, 300, 400 degrees C in an on-line pyrolyzer under anaerobic conditions and in an off-line mode separately. Gas chromatography-mass spectrometry (GC/MS) was used for the qualitative and quantitative analysis of the pyrolysis products. the results. Little geranyl-beta-D-glucopyranoside was pyrolyzed at 200 degrees C and there were a large amount of geraniol and little by-products produced at 300 degrees C. With the increasing temperature to 400 degrees C, both the pyrolytic products and by-products were significantly increased. Therefore, it indicated that the optimized temperature of pyrolysis was 300 degrees C. The main pyrolysis product of the glycoside was geraniol. It showed the primary decomposition reaction took place with the breaking of glycosidic linkage, the cleavage of O-glycosidic bond as expected. The on-line mode experiment was a rapid and good qualitative method for the pyrolysis, and the off-line mode can be used as a quantitative method based on the qualitative analysis.